Check SSL Certificate Validity Dates

by

The Script

echo | openssl s_client -connect YOUR_DOMAIN:443 2>/dev/null | openssl x509 -noout -dates

Explanation

openssl s_client -connect YOUR_DOMAIN:443 – This connects to the server on port 443 which is the default for HTTPS, and fetches the SSL certificate

2>/dev/null – This discards any error messages to keep the output clean

openssl x509 -noout -dates – This extracts the validity dates from the fetched certificate

Variations

  • To view the entire certificate
echo | openssl s_client -connect YOUR_DOMAIN:443 2>/dev/null | openssl x509 -noout -text
  • To check a certificate on a different port (ex., 8443)
echo | openssl s_client -connect YOUR_DOMAIN:8443 2>/dev/null | openssl x509 -noout -dates
  • To check the certificate chain (to see intermediate certificates)
echo | openssl s_client -connect YOUR_DOMAIN:443 -showcerts 2>/dev/null